In recent years, there has been an increasing number of surgeons using surgical staples, rather than conventional sutures. This is true because the use of surgical staples and surgical stapling instruments has rendered many difficult procedures much simpler. Of even more importance, however, is the fact that the use of surgical staples significantly reduces the time required for most procedures and, therefore, reduces the length of time for which the patient must be maintained under anesthetic.
Many types of surgical stapling instruments have been devised for many different procedures. The present invention is directed to a linear surgical stapling instrument. This is an instrument which, on a single actuation, simultaneously implants and forms at least one rectilinear row of surgical staples. Such instruments are used on many different organs and tissues, such as the lung, the esophagus, the stomach, the duodenum, and throughout the intestinal tract.
In its earliest form, the linear surgical stapling instrument was a permanent, multi-use instrument, and the surgical staples were manually loaded into the instrument one-by-one. An exemplary surgical stapling instrument of this type is taught in U.S. Pat. No. 3,080,564. While such instruments performed well, they were, in general, complex in construction, expensive to manufacture, heavy, bulky and difficult both to load with surgical staples and to clean and sterilize after each use.
A significant improvement in the linear surgical stapling instrument came about with the provision of presterilized, disposable loading units or staple cartridges. U.S. Pat. Nos. 3,275,211 and 3,589,589 are exemplary of those relating to permanent, multi-use, linear instruments having replaceable staple cartridges. While this improvement significantly reduced the time previously required for hand-loading of the staples, the basic instrument still had to be disassembled, cleaned, reassembled and sterilized for each procedure, and frequently required additional maintenance and adjustment. Also, if more than one load of staples was required in a given procedure, the cartridge had to be replaced each time, as it contained only a single load.
Even more recently, in view of rising hospital costs, there has been an ever increasing interest in disposable surgical stapling instruments, to eliminate as much work as possible (i.e., disassembling, cleaning, reassembling, sterilization and the like) and to be more efficient, while at the same time not having to compromise the surgical procedures.
Such a disposable linear surgical stapling instrument is taught, for example, in U.S. Pat. No. 4,527,724 This instrument, simple in construction and relatively inexpensive to manufacture, is characterized by a working gap or range of distances between the instrument anvil and the cartridge over which a single size staple can be properly implanted and formed. The proper and desired setting of the instrument, within the working gap, is easily accomplished through simple manipulation of an adjustment knob at the rear of the instrument with indicator means on each side of the instrument to clearly show when the distance between the anvil and the cartridge is within the working gap. In addition, the gap to which the instrument is set can fall anywhere within the confines of the working gap of the instrument. The instrument is provided with an alignment and retaining pin, shiftable to an operable position wherein alignment between the anvil and the staple cartridge is ensured, and wherein tissue to be sutured, located between these elements, is retained therebetween. The instrument is provided with a lockout device which precludes rotation of the adjustment knob to secure the desired gap unless the alignment and retaining pin has been shifted to its operative position. The instrument is also provided with a novel trigger safety which will disable the trigger until the movable jaw of the instrument has been shifted to a position near the working gap.
For purposes of economy and simplicity, much of the instrument is made of appropriate plastic material, while most of the major load-bearing elements of the instrument are metallic. The instrument is so designed that the staple driver is coupled to the trigger at all times. As a result of this, the driver is not free floating and cannot accidentally dislodge or discharge the surgical staples during shipping and handling prior to use of the instrument in the operating room.
As indicated above, linear surgical stapling instruments (whether they be permanent, reusable instruments or disposable, single-use instruments) are characterized by the fact that they simultaneously form and implant at least one rectilinear row of surgical staples. In fact, the most commonly encountered linear surgical stapling instrument simultaneously forms and implants two rectilinear rows of surgical staples, with the surgical staples of one row being offset or staggered with respect to the surgical staples of the other row. This assures reliable suturing of the tissue to be joined together.
It has been found that it would be a matter of great convenience to the surgeon if the staple cartridge would contain more than one load of surgical staples. The word "load" used here and hereinafter refers to that number of staples required to make up the single or double row of staples implanted when the surgical stapling instrument is actuated. This would enable the surgeon to perform two or more suturing procedures before changing cartridges in a permanent or disposable multiple-use instrument or changing instruments in the case of a disposable instrument.
As a consequence, the present invention is directed to a multiple-load cartridge assembly for a linear surgical stapling instrument. Depending upon the materials from which the elements of the cartridge of the present invention are made and the manner in which they are assembled, the cartridge may be provided in a number of forms. For example, the cartridge can constitute a reusable, refillable cartridge to be used with a permanent, nondisposable linear surgical stapling instrument. The cartridge can be a replaceable and disposable cartridge for a permanent instrument. The cartridge can be a reusable, refillable cartridge for a disposable instrument. The cartridge can be a replaceable and disposable cartridge for a disposable instrument. Finally, the cartridge can constitute a permanent part of a disposable instrument, the instrument and cartridge being disposed of when the cartridge is empty.